You are very confused, the pity is only for the S rank characters, getting an A rank does not reset it, and every game resets your pity when you get a S rank, they being the new one from the banner or someone that’s been in the game for a while, but the second time you hit pity will be the banner S rank, just like genshin and star rail.
I think the fact that people treat them different is the argument that, when the company themselves are taking a cut of that RMT, they have a financial incentive to design systems that would make you want to use it, even more so than when it’s something done against the TOS.
It’s why Diablo 3 had to remove it, the grind got much better after it was gone.